Arithmetic and control unit



FIG. 1 is a perspective view of an arithmetic and control unit showing my new design, wherein a lid portion is in the open position;

FIG. 2 is a top plan view thereof, wherein the lid portion is in the open position; and,

FIG. 3 is a reference top plan view thereof, wherein the lid portion is removed.

Portions of FIGS. 1 and 2 that are shown as broken lines and FIG. 3 are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an arithmetic and control unit, as shown and described. 